pg_upgrade: Improve one log message

The parenthesized plural is unnecessary here and inconsistent with
nearby similar messages.

src/bin/pg_upgrade/check.c

@@ -1133,7 +1133,7 @@ check_for_composite_data_type_usage(ClusterInfo *cluster)
 	if (found)
 	{
 		pg_log(PG_REPORT, "fatal");
-		pg_fatal("Your installation contains system-defined composite type(s) in user tables.\n"
+		pg_fatal("Your installation contains system-defined composite types in user tables.\n"
 				 "These type OIDs are not stable across PostgreSQL versions,\n"
 				 "so this cluster cannot currently be upgraded.  You can\n"
 				 "drop the problem columns and restart the upgrade.\n"